1. Technical Field
The present invention relates to a donor substrate and, more particularly, to a donor substrate for laser thermal transfer, and to a fabrication method of an organic light emitting display using the donor substrate.
2. Related Art
In general, at least a laser beam, an acceptor substrate and a donor film are required to use a laser thermal transfer imaging method. The donor film comprises a base film, a light-to-heat conversion layer disposed on the entire surface of the base film, and a transfer layer disposed on the entire surface of the light-to-heat conversion layer. In order to execute such a laser thermal transfer imaging method, the donor film is laminated on the acceptor substrate so that the transfer layer faces the acceptor substrate. Subsequently, a laser beam is irradiated onto the donor film. Accordingly, transfer layer patterns are formed on the acceptor substrate. This technology is disclosed in U.S. Pat. Nos. 5,998,085, 6,214,520, and 6,114,088.
The formation of transfer layer patterns on the acceptor substrate by irradiating the laser beam onto the base film is now described in detail. The laser beam is irradiated onto parts of the base film. At this point, the light-to-heat conversion layer in the areas onto which the laser beam is irradiated absorbs the laser beam, and converts the laser beam to thermal energy. The transfer layer contacting the regions of the light-to-heat conversion layer, from which the thermal energy is generated is transferred to the acceptor substrate selectively by the thermal energy, thereby forming transfer layer patterns. In this case, the width of the transfer layer pattern corresponds to the width of the laser beam. Therefore, if it is intended to minutely form the transfer layer pattern, the width of the laser beam should be adjusted with accuracy. However, the accurate adjustment of the width of the laser beam requires a highly accurate laser apparatus. Such a laser apparatus with high accuracy comes at a high price, thereby causing an increase in the fabrication cost of an organic light emitting display.